I know there are a couple of you guys on this board that own this plasma. I was looking at the differences between this model and the HD one (mainly the price) and wondering if the HD upgrade would be worth the price. I also noticed that this model has a higher contract ratio (4000:1 vs 3000:1) than the HD model. I guess I don't really know what that means. Does that not have as much to do with the picture quality as the resolution?